Disposable injector comprising at least one draw hook and a sliding wedge-type gear for unlocking a locking element

ABSTRACT

A disposable injector with a housing ( 10 ) in which are arranged at least one mechanical spring energy store ( 50 ), at least one cylinder-piston unit that can be filled at least temporarily with an active substance, at least one piston actuation plunger ( 60 ) and at least one triggering unit ( 80 ). The spring energy store comprises at least one pre-loaded spring element. The spring-loaded piston actuation plunger has at least one traction rod ( 61 ) which can be moved transversely, at least in certain regions, and by means of a supporting portion supports the tensioned spring energy store on at least one resting surface ( 37 ) of the housing. An actuatable triggering slide device ( 82 ) unlocks the disposable injector and releases the supporting portion to allow it to move away from the resting surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of and claims the benefit of U.S.patent application Ser. No. 12/587,684 filed Oct. 10, 2009 now issued asU.S. Pat. No. 8,167,840, which application is incorporated herein byreference in its entirety. The said U.S. patent application Ser. No.12/587,684 is a continuation-in-part application of pendinginternational application PCT/EP2008/002391 filed Mar. 27, 2008 andclaiming the priority of German Application No. 10 2007 018 868.6 filedApr. 19, 2007.

BACKGROUND OF THE INVENTION

The invention relates to a disposable injector with a housing in whichor on which are arranged, in each case at least in some areas, at leastone mechanical spring energy reservoir, at least one cylinder/pistonunit that can be filled at least temporarily with active substance, atleast one piston-actuating ram and at least one trigger unit, in whichthe spring energy reservoir comprises at least one pretensioned springelement, in which at least part of the piston-actuating ram ispositioned between the spring energy reservoir and the piston of thecylinder/piston unit, and in which the spring-loaded piston-actuatingram has at least one tension bar which is transversely movable at leastin some areas and which, by means of a support portion, supports thetensioned spring energy reservoir on at least one bearing surface of thehousing.

DE 36 44 984 A1 discloses an automatic injection device which isequipped with an injection needle and in which the injection needle isdriven out by means of a mechanical spring reservoir and, at the sametime, the injectable substance stored in the device is discharged. Thespring element pretensioned in the spring reservoir is held in thehousing of the injection device in the above-described manner. However,the tension bar is secured by means of a button-shaped catch elementthat is to be removed separately counter to the triggering direction.

The object of present invention is providing a disposable injector ofmodular design which, with a small overall size, comprises only a smallnumber of components and, while being easy to handle, ensures safestorage and reliable operation.

SUMMARY OF THE INVENTION

The invention relates to a disposable injector with a housing (10) inwhich are arranged at least one mechanical spring energy store (50), atleast one cylinder-piston unit that can be filled at least temporarilywith an active substance, at least one piston actuation plunger (60) andat least one triggering unit (80). The spring energy store comprises atleast one pre-loaded spring element. The spring-loaded piston actuationplunger has at least one traction rod (61) which can be movedtransversely, at least in certain regions, and by means of a supportingportion supports the tensioned spring energy store on at least oneresting surface (37) of the housing. An actuatable triggering slidedevice (82) unlocks the disposable injector and releases the supportingportion to allow it to move away from the resting surface.

For this purpose, the trigger unit has at least one trigger slide, atleast one trigger lever bearing on the housing, and a catch element thatholds the tension bar in the locked position. The trigger lever ortrigger levers can be displaced by a sliding movement or pivotingmovement of the trigger slide in such a way that the catch elementreleases the tension bar and slides the support portion from the bearingsurface.

With the invention, a needleless disposable injector is made availablewhose piston-actuating ram or parts thereof, upon triggering of thedisposable injector, executes a movement that is oriented transverselywith respect to the longitudinal direction and/or transversely withrespect to the centre line of the disposable injector. For pretensioningand holding the spring energy reservoir, one or more parts of thepiston-actuating ram bear with at least one enclosure or a hook on thehousing or on a structural part arranged on the housing. To trigger thedisposable injector, the enclosures or hooks, after automatic safetyrelease, are pushed down from their bearing surface on the housing, suchthat the piston-actuating ram, under the effect of the spring energyreservoir, can move at least approximately parallel to the centre lineof the disposable injector.

The longitudinal movement of the triggering component derived from apress-button can also take place by means of a rotation movementrelative to the injector housing. For this purpose, the triggeringcomponent is mounted in the injector housing by way of a screw thread.The screw thread and this component have a centre line that is congruentwith the centre line of the injector housing. By means of a suitablerotation movement, the triggering component is moved into the injectorhousing. This results in the longitudinal movement necessary for thesafety release and triggering.

The movement required for the safety release and triggering can also bea pure pivoting movement. For this purpose, a cam or eccentric structurecan be formed integrally on the inside wall of the triggering componentand, by means of the pivoting or rotation of the triggering component,moves certain elements, e.g. trigger levers of the trigger unit.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the invention will become clear from the followingillustrative embodiments represented schematically in the drawings, inwhich:

FIG. 1 shows a disposable injector with a tension bar;

FIG. 2 shows the same as FIG. 1, but released and actuated;

FIG. 3 shows the same as FIG. 2, but after the medicament has beenexpelled;

FIG. 4 shows a disposable injector with an eccentric tension bar;

FIG. 5 shows the same as FIG. 4, but released and actuated;

FIG. 6 shows the same as FIG. 5, but after the medicament has beenexpelled;

FIG. 7 shows a disposable injector with separate trigger levers;

FIG. 8 shows the same as FIG. 7, but after the catch element has beenreleased;

FIG. 9 shows the same as FIG. 8, but actuated;

FIG. 10 shows the same as FIG. 9, but after the medicament has beenexpelled;

FIG. 11 shows a separate ring with trigger levers formed integrallythereon;

FIG. 12 shows a disposable injector with trigger levers formedintegrally on the housing;

FIG. 13 shows the same as FIG. 12, but after the catch element has beenreleased;

FIG. 14 shows the same as FIG. 13, but actuated;

FIG. 15 shows the same as FIG. 14, but after the medicament has beenexpelled;

FIG. 16 shows a perspective view of the housing without safety cap,support sleeve and cylinder/piston unit;

FIG. 17 shows a cross section of the housing in the trigger area;

FIG. 18 shows a detail from FIG. 12.

DETAILED DESCRIPTION OF THE PARTICULAR EMBODIMENTS

FIGS. 1 to 3 show the simplified principle of a disposable injector witha permanently charged spring energy reservoir. The disposable injectorcomprises a housing (10), a for example filled cylinder/piston unit(100), a piston-actuating ram (60) with a tension bar (61), and ahelical compression spring (50) as spring reservoir. The tension bar(61) comprises multiply slit tension hooks (62). In addition, a triggerunit (80), in which a trigger element (82) and a safety cap (90) arearranged, sits on the housing (10).

The housing is a pot-shaped hollow body open at the top and bottom andwith an intermediate base (32). The intermediate base (32) has, forexample, a central opening (34) through which, according to FIG. 1, thetension hooks (62) is engaged. The individual tension hooks (62) liewith their support portions (65) on the bearing surface (37) of thehousing (10).

The piston-actuating ram (60) is divided into three areas. The lowerarea is the piston slide (76). Its diameter is slightly smaller than theinternal diameter of the cylinder (101) of the cylinder/piston unit(100). The lower end face of the piston slide (76) acts directly on thepiston (111).

The middle area is the ram plate (73). The ram plate (73) is a flat andin at least some areas cylindrical disc whose external diameter is a fewtenths of a millimeter smaller than the internal diameter of the housing(10) in the jacket area (31).

The upper area is the tension bar (61) consisting, for example, of twoelastic tensions hooks (62) lying opposite each other. Both tensionhooks (62) lie back to back and seek to force themselves apart in themanner of a leaf spring, such that they bear on the edge (36) of theopening (34) with pretensioning, for example. Their spring direction issymbolized by a helical compression spring (64) lying transverselybetween them as an alternative.

Of course, such a helical compression spring (64) can also really beused if, for example, the tension hooks (62) are articulated on the ramplate (73) by means of pivot hinges. The pivot axes of these pivothinges would then lie transverse to the centre line (5) of the housingand perpendicular to the plane of the drawing according to FIGS. 1 to 3.

The cylinder/piston unit (100) is secured in the lower part of thehousing (10). The cylinder/piston unit (100) here consists of a cylinder(101) which is filled with an injection solution (1) and in which apiston (111) lies in the rear position. Above the piston (111), thepiston-actuating ram (60) is arranged in the housing (10) in such a waythat, for example, although not touching the piston, it is laterallyguided with its lower end in the upper area of the cylinder (101).

The helical compression spring (50) sits pretensioned between the ramplate (73) and the intermediate base (32) of the housing (10).

The trigger unit (80), with a trigger slide (82), several trigger levers(16) and a catch element (95), sits in the upper area of the housing(10), under a safety cap (90).

The catch element (95) is a plate-shaped rotary part with a centralcatch pin (98). The catch element (95) has an edge (96) that extends inthe same direction as the catch pin (98). The edge (96) has afrustoconical outer wall (97) whose theoretical peak lies in front ofthe central catch pin. The peak angle of the outer wall (97) liesbetween 25 and 100 angle degrees. Of course, in the case of two or fourtension hooks (62), the catch element can also be a square or polygonalplate whose outer wall has the shape of a truncated pyramid. In thiscase, the catch pin (98) also has a rectangular cross section.

According to FIG. 1 (see also FIG. 2), the catch element (95) bears onthe tension hook (62), with the catch pin (98) being securely clamped inthe upper area of the slit (69) located between the tension hooks (62).The catch pin (98) here has a rectangular cross section, for example. Itblocks the tension hooks (62) mechanically in their locked position.

The trigger levers (16) arranged in the trigger area bear with theirupper contact zones (18) on the opposite areas of the outer wall (97) ofthe catch element (95). If appropriate, the lower contact zones (19) ofthe trigger levers (16) at the same time touch the upper outer contour(66) of the tension hooks (62). Moreover, the pot-shaped trigger slide(82) bears on the trigger levers (16) mounted on the intermediate base.The trigger slide (82) is initially locked with a form fit in the areaof the upper edge of the housing (10). It bears with an inner edge (83)on the respective outer contour (17) of the individual trigger levers(16).

If appropriate, the trigger levers (16) can be secured on a ring-shapedcomponent (20), see FIG. 7. This component (20) then lies for example onthe intermediate base (32). The trigger levers (16) protrude upwardsfrom it. The portions of the ring-shaped component (20) that are locatedbetween two respective trigger levers can serve, inter alia, as torsionspring.

The outer contour (17) and the contact zones (18, 19) have in general aspherical curvature. However, surfaces (17-19) are also conceivable thathave a flat or plane configuration at least in some areas.

The trigger slide (82), which is mounted on the upper end of the housing(10) in such a way as to be initially locked and longitudinallydisplaceable, bears in a sliding manner on the for example cylindricalinner surface of the trigger area of the housing (10).

To release the disposable injector, the safety cap (90), see FIG. 1, isremoved from the housing (10). The disposable injector is then placed onthe injection site. To trigger it, a finger of the hand holding thedisposable injector is used to press the trigger slide (82), like apress-button, linearly into the housing (10). The inner edge (83) of thetrigger slide (82) presses the trigger levers (16) with the uppercontact zone (18) against the outer wall (97) of the catch element (95)via their outer contour. The catch element (95) is pressed upwards, as aresult of which the catch pin (98) springs from the slit (69), counterto the direction of movement of the trigger slide (82). At the sametime, or also slightly later, the lower contact zone (19) comes to reston the outer contour (66) of the tension hooks (62). By means of theincreasing pivoting of the trigger levers (16), under the thrust of thetrigger slide (82), the support portions (65) of the tension hooks (62)are bent towards the centre line (5) counter to the action of the springelement (64). As a result, the support portion (65), under the effect ofthe helical compression spring (50), slips through the opening (34) intothe interior (11) of the housing (10). In this process, thecylinder/piston unit (100) is emptied, see FIG. 3.

As soon as the for example elastically deformed tension hooks (62) asparts of the piston-actuating ram (60) have reached the interior (11) ofthe housing (10), they spring away from one another again, for example.

The nature of the triggering operation is not restricted to the variantdescribed here. Instead of the longitudinally displaceable trigger slide(82), it is possible, for example, to use an eccentric gear, a screwgear or another lever gear.

FIGS. 4 to 6 show the design plans of a disposable injector that has aneccentric hook-shaped tension bar (62). The latter passes through aneccentric opening (34) of the base (32). The tension bar (62) lies withits support portion (65) on the bearing surface (37). A trigger lever(16) extends upwards from the base (32).

The cap-shaped trigger element (82) sits longitudinally displaceably onthe housing (10). The trigger element (82) has a conical, frustoconicalor pyramidal area (84) and additionally carries in its interior atrigger wedge (86). Its wall has a recess (89) in which, according toFIG. 4, a for example mushroom-shaped safety element (90) is optionallyarranged. The safety element (90) rests on the bearing surface (37).

Between the tension bar (62) and the trigger lever (16), a catch element(95) is located in the trigger unit (80). It bears at the left-hand sideon the trigger wedge (86) and at the right-hand side on the uppercontact zone (18) of the trigger lever (16). At the same time, a part ofthe catch element (95) sits in the recess (34), blocking the tension bar(62).

To release the disposable injector, the safety element (90) is first ofall pulled out of the trigger element (82). The disposable injector isthen triggered by pressing the trigger element (82) down in the mannerof a press-button. The trigger element (82) slides along the outer wallof the housing (10). In doing so, the area (84) first contacts thetrigger lever (16) and presses the latter via the contact zone (16)against the catch element (95). The latter deflects upwards and freesthe recess (34). The trigger wedge (86) then rests on the supportportion (65) of the tension bar (62) and pushes it into the recesses(34), see FIG. 5. The piston-actuating ram (60) released in this wayshoots downwards and in doing so empties the cylinder/piston unit (100).

In this principle, and in the other principles shown here, thepiston-actuating ram (60) can have a separate piston slide (76). Forthis purpose, it is then guided on the inside wall of the housing (10)and/or is mounted on the ram plate (73) by a hinge (77), see FIG. 6.

It is also possible to form the piston slide (76) as piston rodintegrally on the piston (111) and thus to guide the piston rod only bythe piston (111) and/or by contact, in some areas for example, on theinside wall of the cylinder (101). Of course, the piston slide (76) andthe piston rod can share the space between the ram plate (73) and thepiston (111) in any desired way.

FIGS. 7 to 11 show an embodiment of the principle described in FIGS. 1to 3. Here, the supporting component is the housing (10). It has asubstantially tubular shape and is divided into three functional areas(21, 31, 41). According to FIG. 7, the upper area is the trigger area(21). This is adjoined by the jacket area (31). An intermediate base(32) is arranged between the two areas and also protrudes slightlyradially beyond the jacket area (31). The intermediate base (32) has acentral recess (34), the diameter of which widens slightly, for exampletowards the bottom.

In the trigger area (21) of the housing (10), a dimensionally rigid, forexample metal, apertured disc is located on the intermediate base (32),and in this case it is for example countersunk around the bore (34). Itis adhesively bonded or injection-moulded therein. The apertured disc(39) protects the intermediate base (32) from pressures and/or otherdeformations. It also prevents sticking of the components (32) and (65)that are otherwise in contact there.

The fixing area (41) for receiving the insertable cylinder/piston unit(100) is arranged below the jacket area (31). The unslotted fixing area(41) is part of a bayonet catch. For this purpose, two or more angledchannels (42) are arranged on its inner wall. The channels (42) leadvertically upwards from the lower end face (12) of the housing and,after a length of a few millimeters, each merge into a short horizontalchannel portion.

In the fixing area (41), the cylinder (101) is fitted and fixed via twoor more bayonet pins (44). If appropriate, one or more locking elements,that prevent detachment of the bayonet catch, i.e. removal of thecylinder (101), are located in the horizontal channel portion or on atleast some of the bayonet pins (44).

The cylinder (101) is a thick-walled pot, for example. The rodlesspiston (111) sits in the for example cylindrical bore of the cylinder(101). At its front end face, of at least approximately conicalconfiguration, the piston (111) has an axial annular groove (112) forreceiving a sealing ring (114) or a permanently elastic sealingcompound. A for example cylindrical metal plate (116) is let into therear end face of the piston (111).

A short cylindrical, nozzle-like bore (106) is located at the centre ofthe bore of the cylinder (101), whose cylinder base is adapted at leastapproximately to the contour of the front end face of the piston. Thediameter of the bore (106) is approximately 0.1 to 0.5 millimeter. Thisbore (106) is one to five times as long as its diameter. It ends in acylindrical recess (107) of the outer end face (103) at the bottom ofthe cylinder (101).

The spring energy reservoir (50) or the drive unit of the disposableinjector is arranged between the piston (111) and the trigger area (21).The spring energy reservoir (50) is a helical compression springarranged on a piston-actuating ram (60) with four tension hooks (62). Bymeans of the support portions (65) of the tension hooks (62), thehelical compression spring (50) sits tensioned in the housing (10). Itis supported between the inside face of the intermediate base (32) andan upper end face of the piston-actuating ram (60).

The piston-actuating ram (60) is divided into three areas. The lowerarea is the piston slide (76), the middle area is the ram plate (73)bearing the spring element (50), and the upper area is a for examplecylindrical portion (75) adjoined by the bundle of for example fourtension hooks (62). In the jacket area (31) of the housing (10), theportion (75) and the bundle of tension hooks (62) have at leastapproximately a cylindrical envelope surface (63), i.e. their outerwalls have the curvature of a cylinder jacket area. The diameter of theenvelope surface (63) is smaller than the smallest diameter of thespring element (50).

As envelope surface, the support portion (65) here has in some areas afrustoconical jacket and in some areas a cylinder. Both areas are thesame length, for example.

The inner walls of the tension hooks (62) are parts of an envelopesurface (68) having the shape of a frustoconical jacket. This envelopesurface (68) encloses the frustoconical jacket-shaped hollow space (67)located between the tension hooks. The cross sections of the hollowspace (67) increase the further they are from the portion (75). Theradial slits (69) lying between adjacent tension hooks (62) increase insize towards the top, according to FIG. 7, to approximately three timesthe width.

The ram plate (73) according to FIG. 7 has, for example, two grooves(74) lying opposite each other.

The tension hooks (62) fit with their support portions (65) in thetrigger area (21). The support portions (65) lie secured on theintermediate base (32).

In the trigger area (21), a trigger slide (82) sits as part of a triggerunit (80) in its upper position under a safety cap (90). The triggerslide (82) is a pot-shaped body whose front area widens in a funnelshape. The cone angle of this area measures, for example, 90 angledegrees. The inner wall of the funnel-shaped area serves as a slidesurface (84), which ends at a so-called inner edge (83). There, theslide surface (84) merges into an at least approximately cylindricalarea. The size of the hollow space of the cylindrical area is chosensuch that the catch element (95) fits in it in any desired position andin each trigger position of the trigger slide (82).

The trigger slide (82) lies with its slide surface (84) on a group ofeight trigger levers (16). The trigger levers (16) are formed integrallyon a ring (20), see FIG. 11. The ring (20) lies loosely on theintermediate base (32), according to FIG. 7. If appropriate, it can alsobe clamped securely and/or locked on the housing (10). The ring (20) isat least supported on the at least approximately cylindrical inner wallof the trigger area (21).

Here, the individual trigger levers (16) are narrow, for examplehexagonal plates, which are arranged on the ring (20) via a foot (25).The trigger levers (16) have a two-part outer contour (17). According toFIG. 7, the upper part (27) lies on the slide surface (84). The lowerpart (28) extends in a straight line, for example, approximatelyparallel to the inner wall of the trigger area (21). This part (28) ofthe outer contour (17) ends on the ring (20).

Facing the centre line (5), each trigger lever (16) has two activezones. These are an upper contact zone (18) and a lower contact zone(19). According to FIG. 7, the upper contact zone (18) is inclined by 45angle degrees relative to the centre line (5). It contacts the catchelement (95) on the frustoconical outer wall (97) of the latter. Thelower contact zone (19) forms an angle of approximately one angle degreewith the centre line (5). According to FIG. 7, this zone has no contactwith the tension hooks (62).

The outer contour parts (27, 28) and the contact zones (18, 19) areeach, for example, subsidiary surfaces of conical or cylindricaljackets. The centre lines of these jackets are congruent with the centreline (5).

The division of the trigger levers (16) sitting on the ring (20) ischosen such that none of the trigger levers (16) can move into one ofthe slits (69) during the triggering procedure. If appropriate, this isalso ensured by a particular shaping of the slit (69) or of the triggerlevers (16).

The catch element (95), resting according to FIG. 7 on the triggerlevers, has a funnel-shaped configuration. Like the trigger slide (82),the catch element (95) is a rotationally symmetrical component. Itconsists of a plate with a central catch pin (98). The catch pin (98)engages in the upper area of the hollow space (67) located between thetension hooks (62). The plate has, on its underside, a support surface(99) with which it bears on the upper ends of the tension hooks (62).

The safety cap (90), which closes the upper end of the housing (10) andprotects the trigger slide (82) from unwanted actuation, also has apot-shaped configuration. It has an almost flat base (91), which all theway round protrudes slightly beyond the side wall of the safety cap(90), such that the cap (90) can also be flipped away by the thumb ofthe hand holding the disposable injector—in the context of one-handedoperation. Towards the housing (10), it has a shoulder (92), which endsin a circumferential locking bead (94). By means of the shoulder (92),the safety cap (90) sits firmly on the upper end face of the housing(10). The locking bead (94) engages elastically in a groove of thehousing (10) in order to fix the cap (90) securely and, if appropriate,sealingly on the housing (10).

FIG. 8 shows the disposable injector with the safety cap (90) removedand with the trigger slide (82) partially actuated, i.e. partiallypressed down. By means of this partial actuation, the upper contact zone(18) of the trigger levers (16) is pressed against the slide surface(84) of the catch element (95), see FIG. 7. The contact zone (18) slidesalong the slide surface (84) towards the centre line (5). The individualtrigger lever (16) in each case pivots about a horizontal axis, whichlies in the area of the respective foot (25) or in the area of the ring(20).

As a result of the movement of the trigger levers (16), the catchelement (95) is pushed upwards out of the hollow space (67). The triggerlevers (16) now lie on the support portions (65) of the tension hooks(62). By further depression of the trigger slide (82), the lower contactzone (19) is pressed against the support portion (65). In this way, thetension hooks (62) are bent elastically and/or plastically in the radialdirection towards the centre line (5). The support portions (65) aredisplaced, sliding on the intermediate base, in the direction of thecentre line (5). The gap space between the individual tension hooks (62)is substantially used up at least in the area of the support portions(65), see FIG. 9. As soon as the maximum external diameter of thesupport portions (65) is smaller than the diameter of the bore (34), thetension hooks (62) can move downwards under the effect of the springelement (50) and displace the piston (111) by way of the piston slide(76), see FIG. 10.

FIGS. 12 to 18 show a disposable injector variant in which the triggerlevers (16) are formed integrally on the housing (10) and springelastically towards the centre line (5) of the disposable injector. Thehousing (10) is essentially a smooth tube with a flat intermediate base(32) located at the top. A central bore (34) for passage of thepiston-actuating ram (60) is formed in the intermediate base (32).

The fixing area (41) for receiving the insertable cylinder/piston unit(100) is located in the lower area of the housing (10). The fixing area(41) is slit longitudinally, for example four times, see also FIG. 16.The inner wall of this area has a thread (46) for example. According toFIGS. 10 to 15, the fixing area (41) is surrounded by a support sleeve(49) locked on the housing (10).

A cylinder/piston unit (100) is screwed into the thread (46). Itconsists of a cylinder (101) and a piston (111). The cylinder (101) isfor example a thick-walled pot, of which the optionally cylindricalouter wall also has a thread (104) at least in some areas.

The piston-actuating ram (60) sits between the intermediate base (32)and the cylinder/piston unit (100) in the housing (10). All the areas(61, 73, 75, 76) of the piston-actuating ram (60) are shown at leastapproximately from FIG. 7.

Here too, the rear end of the housing (10) is closed by means of asafety cap (90). It is substantially comparable to the one in FIG. 7.However, the housing is slit several times in the trigger area (21), seealso FIGS. 16 and 17, such that the safety cap (90) is designedextending down as far as the intermediate base.

In this embodiment, four broad trigger levers (16), for example, areused that are formed integrally on the intermediate base (32). Thetrigger levers (16), see FIG. 17, have crescent-shaped cross sectionsand each have a central hinge (22), see FIG. 18. This hinge (22)separates the upper contact zone (18) from the lower contact zone (19)and the upper part (27) of the outer contour (17) from the lower part(28) of this contour.

As a bevel at its lower edge, the trigger slide (82) has a broad slidesurface (84) which has the shape of a frustoconical jacket surface andwhose cone angle measures approximately 12 to 16 angle degrees. Thisslide surface (84) already lies flat on the upper part (27) of the outercontour (17) in the locked position (8), see FIG. 18. If the triggerslide (82) is now actuated by pressing it, the upper areas (23) of thetrigger levers (16) pivot towards the centre line (5) independently ofthe lower areas (24) of the trigger levers (16), and, via their uppercontact zone (18), they force the catch element (95) upwards. The lattersprings out of the hollow space (67), see FIG. 13. The upper areas (23)of the trigger levers (16) pivot relative to the lower areas (24) at theelastic hinges (22).

Upon a continuous further movement of the trigger slide (82), the slidesurface (84) slips past the zone with the hinges (22) and now forces thelower areas (24) of the trigger levers (16) against the support portions(65) of the tension hooks (62), see FIG. 14. In doing so, the lowerareas (24) buckle elastically or plastically on the intermediate base(32), but without tearing off at the intermediate base (32). The supportportions (65) push the lower contact zone (19) past the edge (36) intothe bore (34). The piston-actuating ram (60) shoots downwards, see FIG.15.

In this variant, the slide surface (84), the contact zones (18, 19), theouter contour parts (27, 28) and the outer wall (97) can also bespherical surfaces.

Except for the spring elements (50, 64), the apertured disc (39) and theoptionally used metal plate (116) of the piston (111), all parts of thedisposable injector are made of plastics or of materials similar toplastic or to rubber. Individual areas of plastic subjected to a highdegree of loading, for example by Hertzian surface stress, can be platedwith ceramic.

LIST OF REFERENCE NUMBERS

-   1 injection solution; medicament-   5 centre line of disposable injector-   8 locked position-   10 housing, in one piece-   11 housing interior-   12 housing end face, bottom-   16 trigger lever-   17 outer contour-   18 inner contour, top; contact zone, top-   19 inner contour, bottom; contact zone, bottom-   20 ring-   21 trigger area-   22 hinge, film-hinge-   23 area, top-   24 area, bottom-   25 foot-   27 outer contour, upper part-   28 outer contour, lower part-   31 jacket area-   32 intermediate base-   34 opening, bore, recess-   36 housing edge-   37 bearing surface-   39 apertured disc-   41 fixing area for the cylinder/piston unit-   42 channels, angular-   44 bayonet pin-   46 thread, inner thread-   49 support sleeve-   50 spring element, helical compression spring,    -   spring energy reservoir-   60 piston-actuating ram-   61 tension bar-   62 tension hook-   63 envelope surface, bottom-   64 spring element, helical compression spring-   65 support portion-   66 outer contour, envelope surface, top-   67 hollow space between the tension hooks-   68 envelope surface, inner-   69 slits between the tension hooks-   73 ram plate-   74 grooves-   75 portion, e.g. cylindrical-   76 piston slide-   77 hinge-   80 trigger unit-   82 trigger slide, press-button,    -   triggering component-   83 inner edge-   84 slide surface, area-   86 trigger wedge-   89 recess-   90 safety cap-   91 base-   92 shoulder-   94 locking beads, locking lugs-   95 catch element, plate-shaped-   96 edge-   97 outer wall, frustoconical-   98 catch pin-   99 support surface-   100 cylinder/piston unit-   101 cylinder-   103 end face-   104 thread-   106 bore, nozzle-   107 recess in the end face-   111 piston-   112 annular groove-   114 sealing ring-   116 metal plate, magnetic or magnetizable-   120 protective film, adhesive seal

1. A disposable injector comprising: a housing (10) in which or on whichare arranged, in each case at least in some areas, a mechanical springenergy reservoir (50), the housing (10) having a bearing surface (37)proximate a recess (34) therethrough, a cylinder and piston unit (100)that can be filled at least temporarily with active substance, thecylinder and piston unit (100) comprising a piston (111) and a cylinder(101), a piston-actuating ram (60) and a trigger unit (80) in operativearrangement with the cylinder and piston unit (100), the spring energyreservoir (50) includes at least one pretensioned spring element, atleast part of the piston-actuating ram (60) is operatively arrangedbetween the spring energy reservoir (50) and the piston (111) of thecylinder and piston unit (100), the spring-loaded piston-actuating ram(60) includes a tension bar (61) which is transversely movable at leastin some areas between a locked active substance pre-dispensing positionand an unlocked active substance dispensing position and the tension bar(61) includes a support portion (65), the housing (10) has a housingedge (36) proximate the recess (34), the tension bar (61) forms,together with the support portion (65), a tension hook (62) which, inthe locked position, engages over the housing edge (36), the bearingsurface (37) of the housing (10) in supportive relationship with thesupport portion (65), the support portion (65) for supporting thetensioned spring energy reservoir (50) in the locked position, thetrigger unit (80) includes a trigger slide (82), a transversely movabletrigger lever (16) bearing on the housing (10), and a catch element (95)for holding the tension hook (62) in the locked position, the triggerslide (82) has a conical, frustoconical or pyramidal area (84) andcarries in its interior a trigger wedge (86), the tension hook (62), thetrigger lever (16), and the catch element (95) are located in thetrigger unit (80), the catch element (95) bears on the left-hand sidethereof on the trigger wedge (86) and at the right-hand side thereof onan upper contact zone (18) of the trigger lever (16), a part of thecatch element (95) simultaneously sits in the recess (34), blocking thetension hook (62) in the locked position, and the trigger slide (82) inoperative arrangement with the transversely movable trigger lever (16),the trigger slide (82) for displacing transversely the trigger lever(16) by a longitudinal sliding movement or pivoting movement of thetrigger slide (82) for simultaneously pushing the catch element (95)upwardly by forcing the trigger lever (16) inwardly and the triggerwedge (86) simultaneously contacting and releasing the tension hook (62)from the locked position by sliding the support portion (65) from thebearing surface (37) by the trigger wedge (86) pushing the supportportion (65) transversely.
 2. The disposable injector according to claim1, further comprising a safety element (90) resting on the bearingsurface (37).